y轴设置title不生效

                yAxis: {  
                    disabled: false,  
                    disableGrid: false,  
                    splitNumber: 5,  
                    gridType: "dash",  
                    dashLength: 8,  
                    gridColor: "#606060",  
                    fontColor:"#666666",  
                    padding: 10,  
                    showTitle: true,  
                    data: [  
                        {  
                        "calibration": false,  
                        "title": "小时",  
                        "titleFontColor":"#ffffff",  
                        "titleOffsetY": 5  
                        }  
                    ]  
                },  

设置的第一根Y轴的title不生效